The present invention relates to a photo coupler and, more particularly, to photo coupler mold techniques.
The conventional photo coupler mold techniques require that a light transmitting layer, have as a pair of elements a light emitting element and a light responsive element, and an opaque layer is provided to mold the pair of elements together. The light transmitting layer is provided for positioning the pair and allowing light transmittance between them. The opaque layer is formed for preventing the introduction of moisture and external radiation from the surroundings to the pair of elements. At least two distinct mold layers were formed using the conventional photo coupler mold techniques, thus resulting in making the fabricating steps complicated. Moreover, since an interface between the two distinct mold layers was close to the pair of light emitting and light responsive elements, an electric discharge tended to develop through the interface upon the application of high electrical energy to the pair of elements.